COMMUNION, in matters of religion, the being united in doctrine and discipline; in which sense of the word, different churches are said to hold communion with each other.
In the primitive Christian church, every bishop was obliged, after his ordination, to send circular letters to foreign churches, to signify that he was in communion with them. The three grand communions into which the Christian church is at present divided, is that of the church of Rome, the Greek church, and the Protestant church: but originally all Christians were in communion with each other, having one common faith and discipline.